Mammalian chromosome ends or telomeres are tightly regulated by the telomerase that mediates telomere elongation and telomere-binding proteins that cap and protect telomere ends. Telomere DNA normally adopts a closed conformation, capped and protected by a multitude of telomere-binding proteins, to prevent DNA damage and genome instability. Telomeres become open and linear during DNA replication to enable telomerase access for telomere elongation. Exposed and critically short telomeres, as a result of mutations in telomerase and telomere regulators, also become open and susceptible to damage and genome instability, ultimately leading to cancer. Mutations in telomere-binding proteins and the TERT promoter have been identified in a number of cancers. Most cancer cells have up-regulated telomerase expression and activities, and cancer cells appear highly sensitive to perturbations in telomerase activities and telomere capping, making the telomerase attractive for therapeutic targeting. A comprehensive study of telomerase regulators therefore should greatly facilitate our understanding of telomerase dysregulation in cancer and the discovery of new drug targets. We have developed an arrayed whole-genome protein interaction network screening strategy based on the Bi-molecular Fluorescence Protein Complementation (BiFC) assay. A pilot TERT BiFC screen identified several proteins as key components of the telomerase complex, including a protein we named TARP1 that has never been characterized before. We propose here to screen genome wide for cell cycle-dependent regulators of the telomerase, and to examine the mechanisms and function of the TARP1-telomerase complex. We will use inducible TARP1 knockout cells generated by CRISPR/Cas9 as well as mouse xenograft models for these studies. Our work will have important implications in devising effective treatment strategies for cancers that result from telomere dysfunction induced genome instability.

Public Health Relevance

Mammalian telomeres are maintained by the telomerase that mediates telomere elongation and telomere-binding proteins that cap and protect telomere ends. We will examine the consequences of disrupting the regulation of telomerase regulators in cells and animal models. These studies will have important implications in devising effective treatment strategies for cancers that result from telomere dysfunction induced genome instability.

Agency
National Institute of Health (NIH)
Institute
National Cancer Institute (NCI)
Type
Research Project (R01)
Project #
1R01CA211653-01
Application #
9215460
Study Section
Cancer Genetics Study Section (CG)
Program Officer
Witkin, Keren L
Project Start
2017-01-01
Project End
2021-12-31
Budget Start
2017-01-01
Budget End
2017-12-31
Support Year
1
Fiscal Year
2017
Total Cost
Indirect Cost
Name
Baylor College of Medicine
Department
Biochemistry
Type
Schools of Medicine
DUNS #
051113330
City
Houston
State
TX
Country
United States
Zip Code
77030
Liu, Yi; Liu, Feng; Cao, Yizhao et al. (2018) Shwachman-Diamond Syndrome Protein SBDS Maintains Human Telomeres by Regulating Telomerase Recruitment. Cell Rep 22:1849-1860
Zhou, Zhifen; Li, Min; Zhang, Lin et al. (2018) Oncogenic Kinase-Induced PKM2 Tyrosine 105 Phosphorylation Converts Nononcogenic PKM2 to a Tumor Promoter and Induces Cancer Stem-like Cells. Cancer Res 78:2248-2261
Li, Feng; Kim, Hyeung; Ji, Zhejian et al. (2018) The BUB3-BUB1 Complex Promotes Telomere DNA Replication. Mol Cell 70:395-407.e4
Chen, Yuxi; Liang, Puping; Huang, Yan et al. (2017) Glycerol kinase-like proteins cooperate with Pld6 in regulating sperm mitochondrial sheath formation and male fertility. Cell Discov 3:17030
Kim, Hyeung; Li, Feng; He, Quanyuan et al. (2017) Systematic analysis of human telomeric dysfunction using inducible telosome/shelterin CRISPR/Cas9 knockout cells. Cell Discov 3:17034
Liang, Puping; Sun, Hongwei; Sun, Ying et al. (2017) Effective gene editing by high-fidelity base editor 2 in mouse zygotes. Protein Cell 8:601-611